1. Field of the Invention
The present invention relates to a battery. More particularly, the present invention relates to a battery with a structure that simplifies insulating between a container and an electrode assembly inside the container.
2. Description of the Related Art
Generally, a primary battery is not rechargeable, i.e., is deposable. A secondary battery, in contrast, may be recharged. Non-aqueous electrolyte secondary batteries of high energy density have recently been developed as high power secondary batteries. Low power batteries, in which one battery cell is made into a battery pack, may be used to power various portable electronic devices, e.g., cellular phones, laptop computers, camcorders, etc. High power, bulk size batteries may be used for drive motors, e.g., electric motors used in electric vehicles. In these high power batteries, several individual secondary battery cells, to tens of individual secondary battery cells, may be connected in series or in parallel.
Secondary batteries may be classified into different types depending on the external shape of the battery. Two common types of secondary batteries are prismatic-type and cylindrical-type batteries.
A secondary battery may include an electrode assembly. The electrode assembly may include a positive electrode and a negative electrode, which may each have a long, belt-like shape, i.e., a ribbon shape. The electrode assembly may also include a separator, which serves as an insulator interposed between the positive and negative electrodes. The positive electrode, separator and negative electrode may be spiral-wound. Alternatively, the positive electrode, the separator and the negative electrode may be stacked in a multiple layer structure. The electrode assembly is typically housed inside a container, and a cap assembly is mounted on the container to seal the container and complete the battery.
In further detail, where the electrode assembly has a wound structure, leads may be individually fixed to the positive and negative electrodes to collect current generated therefrom. The leads may be connected to external terminals and carry the current generated at the positive and negative electrodes to the external terminals.
For bulk size batteries, e.g., those used for motor driven devices such as hybrid electric vehicles (HEVs), the area of the positive and negative electrodes generally increases as the size of the battery increases. This may result in increased resistance within the battery and, thus, bulk size batteries may include a separate tab to maximize the collecting area and lower the resistance. In particular, uncoated regions of the respective electrodes may be connected with the terminals using the tab.
However, such a structure may require an additional process for wrapping the electrode assembly with an insulating film, in order to prevent electrical contact between the tab and the container, or between the electrode assembly and the container. Wrapping the electrode assembly adds complexity to the manufacturing process and makes the process more costly due to insulating film consumption, increased manufacturing time, etc. Accordingly, there is a need for a simplified battery structure that does not require wrapping the electrode assembly with an insulating film.